Water-soluble organic compounds prepared by reacting a zirconium ester with an amino alcohol are known. For example, Bostwick, in U.S. Pat. No. 2,824,114, disclosed compounds prepared by reacting an alkyl titanium or zirconium ester with a monohydric, dihydric, or trihydric monoamino or diamino alcohol, e.g., di-hydroxyethyl-ethylene diamine. Bostwick suggested using his compounds as dispersing agents and as surface active agents for hydrocarbons and waxes. Beacham et al., in U.S. Pat. No. 2,824,115, disclosed combining organo titanium and organo zirconium compounds with polyhydroxyalkyl alkylene polyamines, e.g., 0.1 mol of N,N,N',N'-tetrakis-(2-hydroxypropyl)-ethylene diamine was combined with 0.1 mol of zirconium tetrachloride in 11.1 mols of water. Beacham et al. suggested that their compounds may be used as dispersing agents, additives to paint and varnish formulations to improve durability, agents for the treatment of wool and animal fibers, and in various textile and cosmetic applications.
The use of zirconium compounds as cross-linking agents is also known. An example of such use was given by Kucera in U.K. patent application GB No. 2 108 122 A. Kucera disclosed reacting a zirconium alkoxide with a dialkanol or trialkanol monoamine. Kucera suggested using the resulting compounds as cross-linking agents in hydraulic fracturing of subterranean formations. The production of oil and gas can be stimulated by the hydraulic fracturing technique, in which a fluid composition is introduced into an oil or gas well at a flow rate and pressure which create and/or extend a fracture into the oil- or gas-containing formation. The fluid composition usually carries a proppant (e.g., sand, bauxite, etc.) which is forced into the fracture by the fluid composition and prevents closure of the formation after the fluid pressure is released. For example, in U.S. Pat. No. 3,888,312, Tiner et al. disclosed hydraulic fracturing of subterranean formations using an aqueous gel prepared from a solvatable polysaccharide which had been cross-linked with ammonium tetralactotitanate(IV) or bis(triethanolamine)bis(isopropyl)-titanium.
Recovery of oil from subterranean formations frequently involves displacing crude oil with a driving fluid, e.g., gas, water, brine, steam, polymer solution, foam, or micellar solution. Ideally, such techniques (commonly called flooding techniques) would provide a bank of oil of substantial depth being driven to a producing well; in practice, that frequently is not the case. Oil-bearing strata are usually heterogeneous, some parts of them being more permeable to a driving fluid than others. As a consequence, channeling frequently occurs so that the driving fluid flows preferentially through zones depleted of oil (so-called "thief" zones) rather than through those parts of the strata which contain sufficient oil to make oil-recovery operations profitable. High permeability zones can also cause undesirable loss of drilling fluids when a well (e.g., water, oil or waste disposal) is being drilled. Misplaced casing perforations or casing leaks are another cause of channeling of the driving fluid through zones of high permeability in the subterranean formations. In addition, casing leaks sometimes occur in the annular region above the injection or production packer, and need to be dealt with whether the leaks occur in high or low permeability zones.
The products of the present invention provide advantages over those of the prior art. Thus, for example, the zirconium-containing compositions of the present invention can be used at higher temperatures than the titanium-containing compositions of the prior art. The latter will decompose at elevated temperatures at which one can still use the zirconium-containing compositions of the present invention. Consequently, the zirconium-containing compositions of the present invention can be used in hotter geologic formations, including those at greater depths in oil and gas wells. In addition, the zirconium-containing compositions of the present invention are better suited as cross-linkers than are those of the prior art in cross-linked gels used in hydraulic fracturing fluids and for plugging leaks and selectively plugging permeable zones.